1. Field of the Invention
The present invention relates to an improved terminal lug which can electrically connect both electric wires and apparatuses such as an electromagnetic valve, etc. and a wiring board provided with the same.
2. Description of the Related Art
Conventionally, a female terminal lug of such a type as being adapted to receive a terminal of an electrical load such as an electromagnetic valve or the like and a wiring board provided with such female terminal lugs are disclosed in Japanese Publication No. 9-117038 of unexamined Patent Application. Referring to FIGS. 6 to 9, the female terminal lug of this type which is applied to an automatic gear box of a vehicle will be described. A female terminal lug 1 as shown in FIG. 8 is formed of a sheet metal by a press work, and comprises a boxlike solderless press-contact part 2 (hereinafter referred to as xe2x80x9cpress-contact partxe2x80x9d), a pair of caulking legs 4 for caulking an electric wire 3 press-fitted in the press-contact part 2, and a terminal contact part 6 including a pair of curved springs 5 which are adapted to elastically contact with each other with contact pressure. The female terminal lug 1 is disposed at a determined position on a back side of a base plate 7 formed of an insulating material, as shown in FIG. 9.
The terminal contact part 6 is clearance-fitted into a recess 9 formed in a flat area 8 of the base plate 7. Meanwhile, the press-contact part 2 is seated on the flat area 8 as shown in FIG. 9. The electric wire 3 is wired through the female terminal lugs 1 which have been disposed at determined positions on the base plate 7 as seen in FIG. 7 by means of a wiring device which is well known means per se. In order to conduct the wiring work, the base plate 7 is turned upside down. The electric wire 3 is arranged in the press-contact parts 2 for an electric connection, and caulked by means of the caulking legs 4 to be fixed. Then, the electric wire 3 between the directly adjacent female terminal lugs 1, that is, between the respective press-contact parts 2 adjacent to each other is cut by means of a wire cutting die (a state of FIG. 7). Thereafter, a cover 10 is placed on the base plate 7 to constitute a wiring board 11, as shown in FIG. 9.
This wiring board 11 is contained in an oil pan 13 of an automatic gear box 12 as shown in FIG. 6. In this case, tab terminals 16 of a plurality of electromagnetic valves 14 for hydraulic pressure control (FIG. 7) arranged in the automatic gear box 12 or tab terminals 16 of connectors 15 at an end part of a wire harness (FIG. 7) are press-fitted into respective terminal contact parts 6 in a vertical direction with respect to the flat area 8. On this occasion, because each of the terminal contact parts 6 is clearance-fitted in the recess 9, a positional displacement between the tab terminal 16 and the terminal contact part 6 will be absorbed if any, while the terminal contact part 6 is relatively displaced within the recess 9. Thus, the tab terminal 16 is fitted in the terminal contact part 6 to be electrically connected.
The above described conventional female terminal lug 1 is provided with only one pair of the caulking legs 4 on one side of the press-contact part 2 and accordingly, the electric wire 3 will receive a stress pulled in a direction of an arrow B, when the electric wire 3 is cut at a position close to a press-contact edge 17 by means of the wire cutting die which will descend from a direction of an arrow A (FIG. 8). For this reason, the press-contact edge 17 will receive an irregular force, and there will be a fear that a force of the press-contact part 2 for holding the electric wire may be remarkably decreased, and reliability of the electrical connection may be lowered. In order to avoid such fears, the cutting work must be conducted carefully, which will require a long working time.
Further, the sheet metal work for integrally forming the female terminal lug 1 comprises steps of conducting a punching press, folding a press-contact plate 18 having the press-contact edge 17 with respect to a vertical wall 2xe2x80x2, folding a flange 19 with respect to the press-contact plate 18, folding all of them with respect to a base part 1xe2x80x2 to form the boxlike press-contact part 2, and caulking the flange 19 by means of a caulking hook 20. Therefore, a number of working steps are required, resulting in an increase of the cost. Furthermore, when the electric wire 3 is arranged in a crooked manner as shown by a mark C in FIG. 8, a counter action to a crooking deformation is always exerted on the press-contact edge 17 and the press-contact force for holding the electric wire will be weakened. Because it is difficult to arrange the electric wire in such a crooked manner and allowability of arranging the electric wire is restricted, there is a drawback that free arrangement of the electric wire, and accordingly, free design of arranging mechanical apparatuses such as the electromagnetic valve etc. will be also restricted.
The present invention has been made to overcome the above described problems, and its object is to provide a terminal lug and a wiring board provided with the same in which the holding force of the press-contact part with respect to an electric wire will not be decreased, and which can be manufactured at a low cost, and is free from restrictions in free arrangement of the electric wire and in free design of arrangement of mechanical apparatuses such as an electromagnetic valve, etc.
In order to solve the above described problems, there is proposed according to the invention, a terminal lug adapted to be mounted on a flat area of a base plate of an insulating material and having integrally a press-contact part to which an electric wire is press-fitted for an electrical connection, and a terminal contact part adapted to be clearance-fitted in a recess formed in the flat area and extended from the press-contact part to receive a terminal for an electric load, which comprises a pair of forward caulking legs and a pair of backward caulking legs provided at a backward and a forward positions of the press-contact part, whereby the electric wire press-fitted in the press-contact part is caulked by means of the forward and backward caulking legs.
According to a second aspect of the invention, the press-contact part is provided with a pair of folding pieces arranged in symmetrically opposed relation with each other, and the electric wire is press-fitted in a gap between a pair of the folding pieces for the electrical connection.
According to a third aspect of the invention, there is also provided a wiring board comprising a plurality of the terminal lugs according to the invention provided on the base plate, wherein the electric wire is wired and arranged in the press-contact parts without interruption, and the electric wire existing between the adjacent terminal lugs whose respective terminal contact parts are opposed with each other is cut between the forward caulking legs.
According to a fourth aspect of the invention, the electric wire existing between the adjacent terminal lugs whose respective terminal contact parts are opposed with each other is wired and arranged in a non-linear manner on the wiring board.
In the wiring board according to a fifth aspect of the invention, a terminal of an electromagnetic valve for controlling hydraulic pressure in an automatic gear box of a vehicle as an electric load is press-fitted into the terminal contact part.
In the wiring board according to a sixth aspect of the invention, terminals of rear combination lamps of a vehicle as an electric load are press-fitted into the terminal contact part.